All devices designed to convert the kinetic energy of wind into mechanical and/or electrical energy, commonly called “wind turbines”, need to contend with the fluctuating nature of the wind. All existing wind turbine devices have to contend with the impact of varying angular velocity on the voltage of the electricity produced. Various accommodations have been conceived to deal with the effects of these variations. These innovations include: variable speed electrical generating systems, blade pitch angle control, overspeed electronic breaking protection, diversion load resistors, mechanical disk brakes, electronic angular velocity moderation keyed to wind speed, anemometers to measure wind speed, and various, innumerable other control devices. With all of these devices, the excess power of the wind is lost and is not used to generate electrical or mechanical energy.
A fixed speed wind turbine generator system must be very mechanically robust, adding to cost. Because the rotor speed cannot be varied, fluctuations in wind speed translate directly into drive train torque fluctuations, causing higher structural loads than with variable speed systems.
A variable speed wind turbine generator system is necessarily more complicated than the fixed speed systems. The variable speed system incorporates a doubly fed induction generator, a wound field synchronous generator, or a permanent magnet synchronous generator. These more complicated designs require electronic power converters which reduce electrical efficiency and add to costs.
Additionally, “lift type” vertical axis wind turbines (“VAWT”) have to contend with the problem of stall caused by rapid change of attack angle which results from excessive angular velocity.
The present invention is designed to convert the excess power of the wind into increased moment of inertia and potential energy, and thereby increased storage of energy, which, when the wind ebbs, is converted into the kinetic energy of the rotor which then generates electric energy. Additional benefits include regulation of angular velocity and prevention of excessive velocities. With the proper specific design, the invention can control the angular velocity within the parameters required by the particular wind turbine and charging system.
The invention, with the proper specific design, can be used with any wind turbine of any size and any orientation. It can be used with a horizontal axis wind turbine by incorporating a worm gear or something comparable to allow for the vertical orientation of the present invention. It can also be used in other applications in which it is useful to smooth the fluctuations of energy input, to store excess energy, and to regulate the angular velocity of any mechanical apparatus.